[Dev] [PATCH] make librechroot target arch agnostic

[Josh Branning]

I agree entirely with the spirit of the patch. In regards to the 
technical detail, I can't really comment.

Josh

On 27/02/18 06:18, Andreas Grapentin wrote:
>
> Hi,
>
> in the light of my attempts to create a riscv64 parabola port, I would
> like to see the following changes made to librechroot.
>
> The patch removes the hard-coded arm cross arch checks in favour of a
> more general approach, that works for more architectures. As a side
> effect, this now also would behave correctly when creating x86 chroots
> on arm, although why anyone would choose to do this is beyond me.
>
> Looks OK?
>
> Cheers,
> Andreas
>
> ---
>   src/chroot-tools/librechroot | 20 ++++++++++++--------
>   1 file changed, 12 insertions(+), 8 deletions(-)
>
> diff --git a/src/chroot-tools/librechroot b/src/chroot-tools/librechroot
> index 27e17bd..750f34c 100755
> --- a/src/chroot-tools/librechroot
> +++ b/src/chroot-tools/librechroot
> @@ -69,17 +69,21 @@ hack_arch_nspawn_flags() {
>   		CARCH="$(uname -m)"
>   	fi
>
> -	if [[ "$CARCH" == armv7h ]] && ! setarch armv7l /bin/true 2>/dev/null; then
> -		# We're running an ARM chroot on a non-ARM processor
> +	case $CARCH in
> +		armv7h) _setarch=armv7l ; _qemuarch=arm    ;;
> +		*)      _setarch=$CARCH ; _qemuarch=$CARCH ;;
> +	esac
> +	if ! setarch $_setarch /bin/true 2>/dev/null; then
> +		# We're running a cross-arch chroot
>
>   		# Make sure that qemu-static is set up with binfmt_misc
>   		if [[ -z $(grep -l -xF \
> -			     -e 'interpreter /usr/bin/qemu-arm-static' \
> +			     -e "interpreter /usr/bin/qemu-$_qemuarch-static" \
>   			     -r -- /proc/sys/fs/binfmt_misc 2>/dev/null \
>   			   | xargs -r grep -xF 'enabled') ]]
>   		then
> -			error 'Cannot cross-compile for ARM on x86'
> -			plain 'This requires a binfmt_misc entry for qemu-arm-static.'
> +			error 'Cannot cross-compile for %s on %s' $CARCH $(uname -m)
> +			plain 'This requires a binfmt_misc entry for qemu-%s-static.' $_qemuarch
>   			prose 'Such a binfmt_misc entry is provided by the %s
>   			       package.  If you have it installed, but still see
>   			       this message, you may need to restart %s.' \
> @@ -88,13 +92,13 @@ hack_arch_nspawn_flags() {
>   		fi
>
>   		# Let qemu/binfmt_misc do its thing
> -		arch_nspawn_flags+=(-f /usr/bin/qemu-arm-static -s)
> +		arch_nspawn_flags+=(-f /usr/bin/qemu-$_qemuarch-static -s)
>
>   		# The -any packages are built separately for ARM from
>   		# x86, so if we use the same CacheDir as the x86 host,
>   		# then there will be PGP errors.
> -		mkdir -p /var/cache/pacman/pkg-arm
> -		arch_nspawn_flags+=(-c /var/cache/pacman/pkg-arm)
> +		mkdir -p /var/cache/pacman/pkg-$CARCH
> +		arch_nspawn_flags+=(-c /var/cache/pacman/pkg-$CARCH)
>   	fi
>   }
>
>
>
>
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